CN104103403B - Dust core and manufacture method thereof - Google Patents

Abstract

The present invention provides a kind of dust core and manufacture method thereof. This dust core is by will have the mixture compression molding of soft magnetic powder and insulating properties jointing material and carry out heat treatment and obtain, it is characterized in that, described insulating properties jointing material has binding resin and glass, the glass transformation temperature of described glass is lower than described heat treated temperature, the content of described glass is relative in the scope that the quality of soft magnetic powder is more than 0.1 mass %, below 0.60 mass %, and described glass at least has P₂O₅、B₂O₃And BaO, P₂O₅Ratio of components a be 40～60mol%, B₂O₃The ratio of components d that ratio of components c is 5～45mol%, SnO that ratio of components b is 2～20mol%, BaO be 0～45mol%, Al₂O₃Ratio of components e be 0～15mol%, and meet the relation of a+b+c+d+e≤100mol%. Dust core according to the present invention and manufacture method thereof, it is possible to increase the heat stability of initial magnetic permeability.

Description

Dust core and manufacture method thereof

The application is divisional application, the application number of its parent application: 201210048332.8, the applying date: 2012.2.28, denomination of invention: dust core and manufacture method thereof.

Technical field

The present invention relates to and there is soft magnetic powder and insulating properties jointing material and for the dust core of choking-winding etc. and manufacture method thereof.

Background technology

For for the booster circuit of hybrid motor vehicle etc. or the dust core of the middle use such as generating, the reactor of converting equipment, transformator and choking-winding, assuming that it is under the environment of the condition of high temperature for a long time, it is desirable to it has the heat stability of magnetic characteristic.

Dust core by the mixture with soft magnetic powder and jointing material (binding resin) carries out press-powder shaping and can apply heat treatment further and obtain. This heat treatment is to improve the process needed for the magnetic characteristic of soft magnetic powder, for this, the resin etc. of good heat stability is being studied as binding resin use.

But, according to current experiment it can be seen that for the structure of conventional dust core, create, by heat resistant test, the problem that permeability deteriorates increase, the heat stability of inductance declines.

[at first technical literature]

[patent documentation]

[patent documentation 1] Japanese Unexamined Patent Publication 2010-251600 publication

[patent documentation 2] Japanese Unexamined Patent Publication 2010-232223 publication

[patent documentation 3] Japanese Unexamined Patent Publication 2009-212385 publication

[patent documentation 4] Japanese Unexamined Patent Publication 2004-143554 publication

[patent documentation 5] Japanese Unexamined Patent Publication 2010-27854 publication

[summary of invention]

[problem that invention to solve]

Patent documentation 1 is about to covering the alcoxide layer dispersing glass powder of soft magnetic metal powder and possessing the invention of the dust core powder of the insulating barrier of covering alcoxide layer further. Additionally, in the invention that patent documentation 1 is recorded, its object is to obtain the dust core of high intensity.

Patent documentation 2 is about the core part with soft magnetic material, the invention that the insulant covering the coating of the particle adhesion of the Ins. ulative material of core part covers soft magnetic powder. Additionally, in the invention that patent documentation 2 is recorded, its object is to the dust core providing eddy current losses little.

Patent documentation 3 is the invention about the composite soft magnetic material with soft magnetic powder and insulating properties jointing material, which describe following content, that is, insulating properties jointing material is crown glass, it is possible to add any a kind in silicone resin, stearate to described composite soft magnetic material. Additionally, in the invention that patent documentation 3 is recorded, its object is to the performance of long term maintenance dust core. At this, iron loss and intensity can be listed at aspect of performance.

Patent documentation 4 is which describing described lining material is by having constituting with insulating properties, heat stability material beyond glass, binding agent and glass and binding agent about the invention covering iron-based powder utilizing lining material to be covered on iron-based powder surface. Additionally, in the invention that patent documentation 4 is recorded, its object is to obtain the dust core being able to ensure that insulating properties and intensity obtain raising.

Patent document 5 discloses that following content, namely, amorphous soft magnetic alloy powder and glass powder are mixed with resin of binding property, their mixture press molding is made formed body, carries out heat treatment with the temperature lower than the crystallized temperature of amorphous soft magnetic alloy powder and form dust core. It addition, in the invention that patent documentation 5 is recorded, its object is to obtain the dust core of low loss.

As it has been described above, in each patent documentation, and it is absent from requiring to possess the document of the heat stability of permeability. Additionally, the patent documentation being also absent from the heat stability for permeability and the material of jointing material being constituted and has improved with heat treated relation. Invention described in patent documentation 5 describes the experiment about iron loss and permeability. But, patent documentation 5, to reduce eddy current losses for the first purpose, has not improved from the viewpoint of permeability to jointing material and with heat treated relation etc. Furthermore it is thinkable that under the experiment condition of patent documentation 5, the addition of jointing material (resin of binding property) is very few and can not substantially ensure that the intensity of dust core.

Summary of the invention

Therefore, the present invention completes to solve above-mentioned conventional problem, its object is to provide the dust core enabling in particular to improve the heat stability of permeability and manufacture method thereof.

The dust core of the present invention is by will have the mixture compression molding of soft magnetic powder and insulating properties jointing material and carry out heat treatment and obtain, it is characterised in that

Described insulating properties jointing material has binding resin and glass,

The glass transformation temperature (Tg) of described glass is lower than described heat treated temperature.

It addition, the manufacture method of the dust core of the present invention is characterised by, including:

Using soft magnetic powder, the operation generating mixture as binding resin and the glass powder mixing of insulating properties jointing material,

By described mixture compression molding, then carry out heat treated operation with the heat treatment temperature higher than the glass transformation temperature of described glass powder (Tg).

According to the present invention, it is conceivable that, the glass comprised in insulating properties jointing material is bonded to each other because of the heat treatment deformation in the manufacturing process of dust core or glass, thereby, it is possible to alleviate the expansion that causes of heat deterioration of binding resin and shrink (it will be appreciated that improving mechanical strength of insulating properties jointing material). I.e., it is possible to it is contemplated that glass is not be only used as the state that filler is distributed in insulating properties jointing material, it plays the effect of the wedge preventing binding resin layer expansion or shrinkage in described insulating properties jointing material.

At this, the permeability of dust core can be expressed by the numerical expression of the Ollendrof of the DC permeability of the aggregation representing ferromagnetism powder.

As the filling rate of soft magnetic powder be η, soft magnetic powder effective counter field coefficient be the intrinsic function that permeability is μ t of N, soft magnetic powder,

[formula 1]

${\mathrm{\μ}}_{\mathrm{dc}}=\frac{\mathrm{\η}\·{\mathrm{\μ}}_0\·({\mathrm{\μ}}_t-{\mathrm{\μ}}_0)}{N\·(1-\mathrm{\η})\·({\mathrm{\μ}}_t-{\mathrm{\μ}}_0)+{\mathrm{\μ}}_0}+{\mathrm{\μ}}_0$

Wherein, μ₀Permeability 4 π × 10 for vacuum^-7Hm^-1。

It is envisioned that for effective counter field coefficient N, when being filled with soft magnetic powder by the magnetic field interaction between the shape of soft magnetic powder or soft magnetic powder, it is possible to make its N more independent than soft magnetic powder little.

As mentioned above, in the present invention, hybrid glass in insulating properties jointing material, now, by selecting the glass (being heated by the temperature high with glass transformation temperature) with the glass transformation temperature (Tg) lower than the heat treatment temperature in the manufacturing process of dust core, glass becomes the wedge of the expansion or shrinkage preventing binding resin layer, thus, it is conceivable that, even if dust core is exposed under the use environment of high temperature for a long time, the interval of soft magnetic powder is not easy to change, and the change of effective counter field coefficient N is little. Thereby, it is possible to reduce the change of initial magnetic permeability.

By with upper type, the heat stability of the initial magnetic permeability that can improve dust core compared with the past.

In the present invention, it is preferred to the content of described glass is relative in the scope that quality is more than 0.1 mass % and below 0.60 mass % of described soft magnetic powder. Thus, it is not only able to obtain and the initial magnetic permeability (initial stage) of (without glass) equal extent in the past, additionally it is possible to improve the heat stability of initial magnetic permeability.

It addition, in the present invention, it is preferred to: described glass at least has P₂O₅、B₂O₃And BaO, P₂O₅Ratio of components a be 40～60mol%, B₂O₃The ratio of components d that ratio of components c is 5～45mol%, SnO that ratio of components b is 2～20mol%, BaO be 0～45mol%, Al₂O₃Ratio of components e be 0～15mol%, and meet the relation of a+b+c+d+e≤100mol%. Experiment described later obtains described glass as glass 2 and glass 3, is not only able to obtain the initial magnetic permeability (initial stage) substantially equal with being not added with the past case of glass, and the heat stability of initial magnetic permeability can be improved.

It addition, in the present invention, Al₂O₃Ratio of components e be preferably 2～15mol%.

It addition, in the present invention, it is preferred to: Li₂The ratio of components f of O is 0～1mol%, CeO₂Ratio of components g be 0～10mol%, TiO₂Ratio of components i be 0～1mol%, and meet the relation of a+b+c+d+e+f+g+h+i=100mol%.

It addition, in the present invention, the glass transformation temperature (Tg) of described glass is preferably in the scope of 280 DEG C～470 DEG C. It addition, the glass transformation temperature of described glass (Tg) is preferably 360 DEG C less than 470 DEG C.

It addition, in the present invention, it is preferred to the thermal coefficient of expansion of described glass is 60～110 (× 10^-7/ DEG C). The thermal coefficient of expansion of described glass is preferably 60～90 (× 10^-7/℃)。

By adjusting glass composition as described above, control glass transformation temperature (Tg), and control thermal coefficient of expansion further such that it is able to be effectively improved the heat stability of initial magnetic permeability.

It addition, in the present invention, described insulating properties jointing material preferably comprises described glass and the particle diameter magnetic particle less than described soft magnetic powder. Thus, it is possible to it is contemplated that in the present invention, by making magnetic particle be present between soft magnetic powder, it is possible to reduce effective counter field coefficient N, and initial magnetic permeability (initial stage) can be improved.

It addition, by adding magnetic particle, it is possible to increase the heat stability of iron loss. At this, the iron loss (core losses) of dust core is divided into generally proportional to measuring frequency magnetic hysteresis loss and square proportional eddy current losses with mensuration frequency. It is envisioned that increase of the caused magnetic hysteresis loss of residual stress of soft magnetic powder being brought because of the above-mentioned increase of effective counter field coefficient N, insulating properties jointing material of iron loss etc. and become big. Therefore, it is conceivable that, by adding magnetic particle in insulating properties jointing material as the present invention, and the combination etc. to the magnetic particle of insulating properties jointing material interpolation with glass, even if under the use environment being exposed to high temperature for a long time, it also is able to obtain the high mechanical properties of insulating properties jointing material, and also can effectively suppress the variation of residual stress, it is possible to increase the heat stability of initial magnetic permeability and iron loss.

In the present invention, the content of described magnetic particle is in the scope less than 0 mass % and below 0.60 mass % preferably with respect to the quality of described soft magnetic powder. Now, described magnetic particle is oxidate magnetic material, is specifically preferably NiZn ferrite and the ferritic at least one party of MnZn. Thus, it is not only able to improve initial magnetic permeability (initial stage), but also the heat stability of initial magnetic permeability and iron loss can be effectively improved.

[invention effect]

Dust core according to the present invention and manufacture method thereof, it is possible to increase the heat stability of initial magnetic permeability.

Additionally, by not only adding glass to insulating properties jointing material but also adding the magnetic particle that particle diameter is less than soft magnetic powder, it is possible to increase initial magnetic permeability (initial stage), additionally, the heat stability of initial magnetic permeability can not only be improved, and the heat stability of iron loss can be improved.

Accompanying drawing explanation

Fig. 1 is the axonometric chart of dust core (iron core).

Fig. 2 is the top view of coil-embedded dust magnetic core.

Fig. 3 is the enlarged partial sectional view (schematic diagram) of the dust core of embodiments of the present invention.

Fig. 4 indicates that the initial magnetic permeability (initial stage) of the dust core being added with the glass 1 that glass transformation temperature (Tg) is 280 DEG C and the curve chart of the interdependence of iron loss (initial stage) and glass addition.

Fig. 5 indicate that the dust core being added with the glass 1 that glass transformation temperature (Tg) is 280 DEG C is applied heating-up temperature be 180 DEG C and 250 DEG C, heat time heating time when being the heat resistant test of 1000 hours, the curve chart of the interdependence of the rate of change (%) of initial magnetic permeability after described heat resistant test and iron loss variable quantity (%) and glass addition.

Fig. 6 indicates that the initial magnetic permeability (initial stage) of the dust core being added with glass 2 and glass 3 respectively and the curve chart of the interdependence of iron loss (initial stage) and glass addition.

Fig. 7 indicate that the dust core being added with glass 2 and glass 3 respectively is applied with heating-up temperature be 200 DEG C and 250 DEG C, heat time heating time when being the heat resistant test of 1000 hours, the curve chart of the rate of change (%) of initial magnetic permeability after described heat resistant test and the interdependence of glass addition.

Fig. 8 indicate that the dust core being added with glass 2 and glass 3 respectively is applied with heating-up temperature be 200 DEG C and 250 DEG C, heat time heating time when being the heat resistant test of 1000 hours, the curve chart of iron loss rate of change (%) after described heat resistant test and the interdependence of glass addition.

Fig. 9 indicates that the curve chart of the initial magnetic permeability (initial stage) being added with the ferritic dust core of NiZn (but being not added with glass) and iron loss (initial stage) and the interdependence of NiZn ferrite addition.

Figure 10 indicate that to be added with the ferritic dust core of NiZn (but being not added with glass) be applied with heating-up temperature be 200 DEG C and 250 DEG C, heat time heating time be the heat resistant test of 1000 hours when, the curve chart of the rate of change (%) of initial magnetic permeability after described heat resistant test and iron loss rate of change (%) and the interdependence of NiZn ferrite addition.

Figure 11 indicates that the curve chart of the initial magnetic permeability (initial stage) that compound is added with glass 2 and glass 3 and the ferritic dust core of NiZn and iron loss (initial stage) and the interdependence of glass addition.

Figure 12 indicate that compound is added with glass 2 and glass 3 and the ferritic dust core of NiZn be applied with heating-up temperature be 200 DEG C and 250 DEG C, heat time heating time when being the heat resistant test of 1000 hours, the curve chart of the rate of change (%) of initial magnetic permeability after described heat resistant test and glass addition interdependence.

Figure 13 indicate that compound is added with glass 2 and glass 3 and the ferritic dust core of NiZn be applied with heating-up temperature be 200 DEG C and 250 DEG C, heat time heating time when being the heat resistant test of 1000 hours, the curve chart of iron loss rate of change (%) after described heat resistant test and the interdependence of glass addition.

Figure 14 indicates that the curve chart of the relation of the glass transformation temperature of the glass in the multiple dust cores containing glass, the thermal coefficient of expansion of glass and initial magnetic permeability (initial stage).

Figure 15 indicates that the curve chart of the relation of the glass transformation temperature of the glass in the multiple dust cores containing glass, the thermal coefficient of expansion of glass and iron loss (initial stage).

Figure 16 be with the glass transformation temperature of glass be transverse axis, represent with the thermal coefficient of expansion of glass for the longitudinal axis the multiple dust cores containing glass are applied with heating-up temperature be 200 DEG C, heat time heating time be the heat resistant test of 1000 hours when, the curve chart of the rate of change (%) of initial magnetic permeability after described heat resistant test.

Figure 17 be with the glass transformation temperature of glass be transverse axis, represent with the thermal coefficient of expansion of glass for the longitudinal axis the multiple dust cores containing glass are applied with heating-up temperature be 200 DEG C, heat time heating time be the heat resistant test of 1000 hours when, the curve chart of iron loss rate of change (%) after described heat resistant test.

[symbol description]

1,3 dust core

2 coil-embedded dust magnetic cores

4 coils

5 soft magnetic powders

6 insulating properties jointing materials

7 emptying apertures

Detailed description of the invention

Fig. 1 is the axonometric chart of dust core (iron core), and Fig. 2 is the top view of coil-embedded dust magnetic core. Fig. 3 is the enlarged partial cross section (schematic diagram) of dust core.

Dust core 1 shown in Fig. 1 by being compressed shaping and carrying out heat treatment and obtain to the mixture with soft magnetic powder and insulating properties jointing material.

Symbol 5 shown in Fig. 3 is soft magnetic powder, and symbol 6 is insulating properties jointing material. As it is shown on figure 3, insulating properties jointing material 6 surrounds the surface of soft magnetic powder 5, and it is present in and keeps (supporting) multiple soft magnetic powder 5 between soft magnetic powder 5.

It addition, as it is shown on figure 3, be formed with emptying aperture 7 on insulating properties jointing material 6 everywhere. It should be noted that in figure 3, not to all of soft magnetic powder 5 and emptying aperture 7 diacritic.

Coil-embedded dust magnetic core 2 shown in Fig. 2 is configured to the coil 4 having dust core 3, being covered by described dust core 3. The inside of dust core 3 is constituted in the same manner as Fig. 3.

Soft magnetic powder 5 is the amorphous soft magnetic powder such as utilizing water atomization to make. Described amorphous soft magnetic powder (Fe base metal glass alloy powder) such as composition formula is by Fe_{100-a-b-c-x-y-z-t}Ni_aSn_bCr_cP_xC_yB_zSi_tRepresent, 0at%≤a≤10at%, 0at%≤b≤3at%, 0at%≤c≤6at%, 6.8at%≤x≤10.8at%, 2.0at%≤y≤9.8at%, 0at%≤z≤8.0at%, 0at%≤t≤5.0at%.

The average crystallite particle diameter (D50) of soft magnetic powder 5 is 10 μm～about 70 μm. At this, in the present embodiment, soft magnetic powder 5 is not limited to amorphous, but for use amorphous soft magnetic powder and insulating properties jointing material and for dust core that press-powder shapes, it has ratio saturated flux density bigger when using soft magnetic ferrite etc., is thus advantageous to miniaturization.

Insulating properties jointing material 6 shown in Fig. 3 is configured to have binding resin and glass.

Binding resin is silicone resin, epoxy resin, phenolic resin, urea resin, melmac etc.

Especially, for binding resin, it is suitably used as the silicone resin of thermally stable resins.

The binding resin of about 0.5～5.0 mass % is added relative to the quality of the soft magnetic powder 5 contained by dust core.

In the present embodiment, as it has been described above, insulating properties jointing material 6 contains glass. At this, it is contemplated that glass dispersible is in binding resin layer.

Glass together mixes with soft magnetic powder 5, binding resin etc. with Powdered at first, about the shape of the dust core 1,3 shown in Fig. 1, Fig. 2 being compressed the heat treatment after shaping, in the present embodiment, this heat treatment is to carry out with the temperature higher than the glass transformation temperature of glass (Tg).

Therefore, in the present embodiment, it is contemplated that glass is such as from initial Powdered being deformed or produce glass combination each other, spreading to the part in resin and the fusion etc. of resin.

In the present embodiment, multiple soft magnetic powder 5 is kept by the binding resin layer that Young's modulus is little, and further glass lower than the heat treatment temperature carried out in the manufacturing process of dust core for glass transformation temperature (Tg) is put into insulating properties jointing material 6, thus it is constructed to be permeable to alleviate the expansion because the heat deterioration of binding resin layer causes and contraction. It is conceivable that, glass (powder) is exposed in the heat treatment higher than glass transformation temperature (Tg), thus be deformed, glass combination etc. each other, thus, described glass plays the effect as the wedge preventing the expansion of binding resin layer, contraction.

As determine dust core 1,3 permeability factor one of, there is effective counter field coefficient N. About effective counter field coefficient N, it is envisioned that as it is shown on figure 3, when being filled with multiple soft magnetic powder 5, by the mutual magnetic action etc. each other of close soft magnetic powder 5, effective counter field coefficient N becomes the effective counter field coefficient N little value more independent than soft magnetic powder 5.

Under the use environment being exposed to high temperature for a long time, if the change at the interval between each soft magnetic powder 5 is little, then effectively the change of counter field coefficient N is also little.

As mentioned above, in the present embodiment, it is conceivable that, the glass with the glass transformation temperature (Tg) lower than the heat treatment temperature applied in the manufacturing process of dust core can alleviate the expansion because the heat deterioration of binding resin layer causes, contraction, even if under the use environment being exposed to high temperature for a long time, the change also being able to make the interval between the soft magnetic powder 5,5 in dust core 1,3 is little than ever, therefore, it is possible to reduce the change of effective counter field coefficient N.

Based on above content it can be seen that according to present embodiment, the heat stability of the initial magnetic permeability that can improve dust core 1,3 compared with the past. Therefore, it is possible to improve the heat stability of inductance.

In the present embodiment, the content of glass preferably falls in relative to the quality of soft magnetic powder 5 is in more than 0.1 mass % (wt%) and 0.60 mass % (Wt%) scope below.If the addition of glass is too much, it is contemplated that during the formation of dust core, the interval between the soft magnetic powder 5,5 at (initial stage) becomes big, thus effectively the value of counter field coefficient N itself also becomes big, initial magnetic permeability is easily reduced.

In the present embodiment, by limiting the addition of glass as described above, it is possible to obtain and the initial magnetic permeability (initial stage) of (without glass) equal extent in the past, and also the heat stability of initial magnetic permeability can be improved. At this, initial magnetic permeability (initial stage) refers to, dust core formed time (initial stage), be exposed under applied at elevated temperature environment before initial magnetic permeability.

It addition, glass is configured at least have P₂O₅、B₂O₃And BaO, and P₂O₅Ratio of components a be 40～60mol%, B₂O₃The ratio of components d that ratio of components c is 5～45mol%, SnO that ratio of components b is 2～20mol%, BaO be 0～45mol%, Al₂O₃Ratio of components e be 0～15mol%, it is preferable that meet the relation of a+b+c+d+e≤100mol%.

For the compositing range of this glass, by containing the glass 2,3 in experiment described later, and suitably control glass transformation temperature (Tg) according to this glass, it is thus possible to make initial magnetic permeability (initial stage) and the past case being not added with glass roughly equal, and the heat stability of initial magnetic permeability can be improved.

In addition, it is in more than 0.1 mass % (wt%) and 0.60 mass % (Wt%) scope below by making the content of the glass of above-mentioned composition fall into relative to the quality of soft magnetic powder 5, thus, according to experiment described later, it is capable of the raising of the heat stability of initial magnetic permeability, and can make iron loss (initial stage) for (without glass) in the past below further.

It addition, in the present embodiment, Al₂O₃Ratio of components e be preferably 2～15mol%. It addition, P₂O₅Ratio of components a be preferably 41～55mol%. It addition, B₂O₃Ratio of components b be preferably 2～15mol%. It addition, the ratio of components c of BaO is preferably 5～30mol%. The ratio of components d of SnO is preferably 0～30mol%, more preferably 25～30mol%. It addition, Al₂O₃Ratio of components e be more preferably 2～10mol.

Furthermore, in the present embodiment, Li can also be comprised in addition to the foregoing₂O、CeO₂、TiO₂In at least one. In this case, Li₂The ratio of components f of O is 0～1mol%, CeO₂Ratio of components g be 0～10mol%, TiO₂Ratio of components i be 0～1mol%, it is preferable that meet the relation of a+b+c+d+e+f+g+h+i=100mol%.

For for the heat treatment will implemented after there is the mixture compression molding of soft magnetic powder 5 and insulating properties jointing material 6, this heat treatment in eliminating the deformation (askew body) of soft magnetic powder 5 and obtain good magnetic characteristic it is critical that operation. Therefore, heat treated optimum temperature depends on soft magnetic powder 5, in the present embodiment, selects the glass with the glass transformation temperature (Tg) lower than (the best) heat treatment temperature carried out in the manufacturing process of dust core.

The glass transformation temperature (Tg) of the glass in present embodiment is preferably 280 DEG C～about 470 DEG C. It addition, glass transformation temperature (Tg) is preferably 360 DEG C less than 470 DEG C. It addition, glass transformation temperature (Tg) is more preferably 440 DEG C less than 470 DEG C.

By having the glass of above-mentioned composition, it is possible to make glass transformation temperature (Tg) fall in above-mentioned scope.

Furthermore it is thinkable that when (heat treatment temperature-glass transformation temperature (Tg)) is less big, it is possible to make these both sides of heat stability of high initial magnetic permeability be effectively improved. In addition it is possible to the iron loss (core losses) at initial stage is set below the degree becoming equal with the past case without glass.At this, " iron loss at initial stage " refers to, when dust core is formed (initial stage) be exposed to high temperature use under environment before iron loss.

Specifically, (heat treatment temperature-glass transformation temperature (Tg)) is about 2～100 DEG C, it is preferred to about 2～28 DEG C.

Furthermore, it is contemplated that control the thermalexpansioncoefficientα of glass together preferably together with glass transformation temperature (Tg), it is possible to improve the heat stability of initial magnetic permeability. As thermalexpansioncoefficientα, it is preferred to 60～110 (× 10^-7/ DEG C), more preferably 60～90 (× 10^-7/℃)。

Furthermore, in the present embodiment, it is preferable that disperse, to insulating properties jointing material 6, the magnetic particle that particle diameter is less than soft magnetic powder 5. The particle diameter of magnetic particle is just can generally into the little particle diameter of this degree when substantially not making described interval expand in the interval when between the soft magnetic powder 5,5 shown in Fig. 3, specifically, magnetic particle is nanoparticle thus becoming the particle diameter more sufficiently small than soft magnetic powder 5. For magnetic particle, it is possible to select the material different from soft magnetic powder 5.

Such as, magnetic particle is preferably and aoxidizes Magnaglo, specifically at least one party in NiZn ferrite or MnZn ferrite.

So, it is contemplated that by making insulating properties jointing material 6 does not contain only glass but also containing magnetic particle, it is possible to make described magnetic particle be present between soft magnetic powder 5,5, it is possible to reduce the value of effective counter field coefficient N itself. Thereby, it is possible to make the initial magnetic permeability of dust core 1,3 be improved.

It addition, by adding magnetic particle, it is possible to increase the heat stability of iron loss. As one of factor reducing iron loss, it is possible to enumerate the situation that soft magnetic powder 5 subjected to stress (residual stress) of sening as an envoy to reduces. At this, it is conceivable that, by adding the combination etc. of magnetic particle and magnetic particle and glass in insulating properties jointing material 6, it is not only able to for the mechanical strength using environments to improve insulating properties jointing material 6 being exposed to high temperature for a long time, and can effectively suppress the variation of residual stress relative to soft magnetic powder 5, thereby, it is possible to improve the heat stability of initial magnetic permeability and iron loss.

In the present embodiment, the content of magnetic particle preferably fall in relative to the quality of soft magnetic powder 5 be more than 0 mass %, below 0.60 mass % scope in.

By as described above to being adjusted to the glass of interpolation in insulating properties jointing material 6 and the addition of magnetic particle in the present embodiment, according to experiment described later, it is possible to be effectively improved the heat stability of initial magnetic permeability and iron loss. It addition, initial magnetic permeability (initial stage) can be set as more than the degree equal with past case (without glass also without magnetic particle). The iron loss at initial stage example than ever (without glass also without magnetic particle) is slightly higher, but is also in spendable scope.

Hereinafter, the manufacture method of the dust core of present embodiment is described.

First, the soft magnetic powder utilizing water atomization etc. to make, binding resin, glass powder, lubricant, cement are stirred together with solvent, mix, thus making the slip of pureed. And the magnetic particle such as NiZn ferrite, MnZn ferrite can be mixed further.

At this, as lubricant, it is possible to use stearic acid Asia lead, aluminium stearate etc. It addition, as cement, it is possible to use silane connecting agent etc.

Above-mentioned slip is put in existing prilling granulator, makes the solvent wink-dry of slip, thus generating the granular mixture by having soft magnetic powder and insulating properties jointing material.

It follows that described mixture is filled in finishing die, thus compression molding is the shape of dust core. Then, dust core is implemented heat treatment. Heat treatment now carries out at the temperature higher than the glass transformation temperature of glass (Tg). Now, owing to pre-determining best heat treatment temperature to eliminate the deformation of soft magnetic powder, so being the temperature higher than glass transformation temperature (Tg) by treatment temperature set, select the glass with the glass transformation temperature (Tg) lower than heat treatment temperature for this.

It is envisioned that by this heat treatment, lubricant substantially gasifies and disappears, thus integrated with binding resin. A part for binding resin also gasifies and disappears. In the present embodiment, glass and binding resin are together present between soft magnetic powder as a part for insulating properties jointing material 6. Glass is making stage of slip as described above as Powdered and be mixed into, but, after compression molding and heat treatment, glass starts deformation from Powdered, or glass becomes the state etc. being bonded to each other, such that it is able to it is contemplated that glass is not only simple filler, it also has the effect of the wedge preventing the expansion of binding resin layer, contraction in insulating properties jointing material.

The dust core of present embodiment has the heat stability of excellent initial magnetic permeability and iron loss. Therefore, the reactor that is particularly suitable for using in the boosting loop of hybrid motor vehicle etc., generating converting equipment, transformator, choking-winding etc. require the purposes under long hot environment with heat stability.

[embodiment]

(obtaining the experiment of the use level of glass 1 and the characteristic of dust core and the relation of heat stability)

The Fe that water atomization will be used to make_74.43at%Cr_1.96at%P_9.04at%C_2.16at%B_7.54at%Si_4.87at%It is that amorphous soft magnetic powder, silicone resin, stearic acid Asia lead and phosphoric acid glass powder (glass 1) mix and make mixture. This phosphoric acid glass uses the oxygen AGCTECNOGLASS KF9079 powder made. The glass transformation temperature (Tg) of glass 1 is 280 DEG C. Additionally, the use level of the silicone resin in described mixture is 1.4wt% relative to the quality of soft magnetic powder, the use level of stearic acid Asia lead is 0.3wt% relative to the quality of soft magnetic powder, and the use level of glass powder is 0wt%, 0.3wt%, 0.6wt%, 1.2wt%, 2.4wt%, 4.2wt% and 6.1wt% relative to the quality of soft magnetic powder.

It follows that fill described mixture in mould, under contact pressure 1470MPa, carry out press molding, thus making the ring-type test portion of external diameter 20mm × internal diameter 12mm × thickness 6.8mm. The ring-type test portion obtained is carried out in stream of nitrogen gas atmosphere at 470 DEG C the heat treatment of 1 hour, thus making dust core.

The intrinsic resistance utilizing the SuperMegohmmeter (DKK-TOA SM-8213) the ring-type dust core to obtaining is measured, the coiling of copper cash is carried out to ring-type dust core, use ImpedanceAnalyzer (HP4192A) to measure initial magnetic permeability, use BHAnalyzer (the rugged communication system of rock) to measure iron loss (initial stage) when frequency 100kHz, Bm=100mT. In heat resistant test, after being put in an atmosphere by ring-type dust core in the drying oven of 180 DEG C, 250 DEG C and keeping 1000 hours, determine initial magnetic permeability and iron loss. Each measurement result illustrates in Table 1.

[table 1]

Fig. 4 indicates that the addition of the glass 1 of each dust core shown in table 1 and the curve chart of initial magnetic permeability (initial stage) and the relation of iron loss (initial stage). It can be seen that the increase of addition along with glass 1 according to table 1 and Fig. 4, initial magnetic permeability reduces, and on the other hand, iron loss increases to some extent. If glass addition is more than 0.6wt%, then initial magnetic permeability declines more than 10% relative to the No.1 (past case) being not added with glass, and on the other hand, iron loss increases by more than 40%. It follows that the reduction of the magnetic characteristic in order to prevent dust core, it is necessary to make glass addition become below 0.6wt%.

Additionally also knowing that, the intrinsic resistance of the dust core shown in table 1 shows the tendency of increase along with the increase of the addition of glass 1, owing to any one test portion is 10⁶More than Ω cm, thus having sufficiently high value as dust core.

Fig. 5 indicate that each dust core of his-and-hers watches 1 implement heating-up temperature be 180 DEG C and 250 DEG C, heat time heating time when being the heat resistant test of 1000 hours, the curve chart of the relation of the rate of change (%) of initial magnetic permeability after the addition of glass 1 and described heat resistant test and iron loss variable quantity (%). At this, " rate of change of initial magnetic permeability " is represented by [initial magnetic permeability at (initial magnetic permeability at the initial magnetic permeability-initial stage after heat resistant test)/initial stage] × 100 (%). (initial stage) and the initial magnetic permeability before being exposed under applied at elevated temperature environment during the formation that " initial magnetic permeability at initial stage " is dust core.

It addition, " iron loss rate of change " is represented by [iron loss at (iron loss at the iron loss-initial stage after heat resistant test)/initial stage] × 100 (%). " iron loss at initial stage " refers to, when dust core is formed (initial stage) and be exposed to high temperature use under environment before iron loss.

Target as heat stability, for the rate of change of initial magnetic permeability, it is set to after 180～200 DEG C × 1000 hours as within ± 15%, it is preferred within ± 10%, it was within ± 25% after 250 DEG C × 1000 hours, it is preferably within ± 20%, it addition, for iron loss rate of change, it is set to after 180～200 DEG C × 1000 hours as within ± 40%, it is preferably within ± 30%, was within ± 70% after 250 DEG C × 1000 hours, it is preferred to ± 50%.

It can be seen that the increase of addition along with glass 1 according to table 1 and Fig. 5, the rate of change (%) of the initial magnetic permeability after heat resistant test is although being negative value, but it has the tendency of reduction as absolute value. In addition we know, iron loss rate of change (%) also has the tendency of reduction. If the addition of glass 1 is more than 1.2wt%, can more efficiently meet the target of above-mentioned heat-resistant stability, but, as shown in table 1 and Fig. 4, it is known that there are the following problems, that is, the addition of glass is more than 1.2wt%, thereby results in that initial magnetic permeability (initial stage) is low and iron loss (initial stage) becomes big.

Known on the other hand, if the addition of glass 1 is below 0.6wt%, although the rate of change of the initial magnetic permeability after then 250 DEG C × 1000 hours is little over-20%, but the rate of change of the initial magnetic permeability after 180 DEG C × 1000 hours maintains-2%～-3% so relatively low value. In addition we know, for iron loss, if the addition of glass 1 is below 0.6wt%, then the iron loss rate of change after 180 DEG C × 1000 hours is able to maintain that within 30%.

(manufacture of glass 2,3)

Glass 2,3 is generated by following manufacture method.

Frit use sell on the market former phosphoric acid, boron oxide element powder, barium carbonate powder, stannic oxide powder, alumina powder.These raw materials are measured and becomes the use level of regulation, be then placed in platinum crucible and be pre-mixed, use electric furnace to dissolve in air atmosphere subsequently. The design temperature of electric furnace is set as 1000～1300 DEG C.

Then, take out platinum crucible from electric furnace, glass is dissolved body and casts in cast iron casting mould and obtain glass. Carry out pulverizing this glass being used in mortar ball mill after coarse pulverization and obtain glass powder.

Additionally, the glass blocks of 3mm × 3mm × 20mm is cut out from a part for the glass of casting, then carry out eliminating the annealing of deformation, use hot device analysis device (motor TMA8310 of science) to measure glass transformation temperature, yield temperature and thermal coefficient of expansion subsequently. The use level of each glass 2,3 made illustrates in table 2 with glass transformation temperature, yield temperature and thermal coefficient of expansion.

[table 2]

(obtaining the experiment of the use level of glass 2,3 and the characteristic of dust core and the relation of heat stability)

The Fe that water atomization will be used to make_77at%Cr_1at%P_9.23at%C_2.2at%B_7.7at%Si_2.87at%It is that amorphous soft magnetic alloy powder, silicone resin, stearic acid Asia be plumbous and pulverous glass 2 or pulverous glass 3 mix and makes mixture.

At this, as shown in table 2, the glass transformation temperature (Tg) of glass 2 (acid glass) is 468 DEG C, lower 2 DEG C than the heat treatment temperature (470 DEG C) implemented in the manufacturing process of dust core. It addition, the glass transformation temperature of glass 3 (acid glass) is 442 DEG C, lower 28 DEG C than the heat treatment temperature (470 DEG C) implemented in the manufacturing process of dust core.

Additionally, the use level of the silicone resin in mixture is 2.0wt% relative to the quality of soft magnetic powder, the use level of stearic acid Asia lead is 0.3wt% relative to the quality of soft magnetic powder, and the use level of each glass 2,3 is 0wt%, 0.1wt%, 0.3wt%, 0.6wt% relative to the quality of soft magnetic powder.

It follows that be filled in mould by described mixture, carry out press molding with contact pressure 1470MPa, thus making the ring-type test portion of external diameter 20mm × internal diameter 12mm × thickness 6.8mm. The ring-type test portion obtained is carried out in stream of nitrogen gas atmosphere at 470 DEG C the heat treatment of 1 hour, thus making dust core.

Quality according to the ring-type dust core obtained and profile cun method calculate the density of magnetic core, and the numerical computations of collaboration amount goes out the occupation rate of soft magnetic powder. The calculating formula of the occupation rate of soft magnetic powder is as follows.

[formula 2]

Next, SuperMegohmmeter (SM-8213 of DKK-TOA) is used to measure the intrinsic resistance of ring-type dust core, it is wound around copper cash to ring-type dust core, use ImpedanceAnalyzer (HP4192A) to measure initial magnetic permeability, use BHAnalyzer (the rugged communication system of rock) to measure iron loss when frequency 100kHz, Bm=100mT. In heat resistant test, ring-type dust core is put in an atmosphere after the drying oven of 200 DEG C, 250 DEG C keeps 1000 hours, measure initial magnetic permeability and iron loss. Each measurement result illustrates in table 3.

[table 3]

It should be noted that dust core No.9～11 shown in table 3 use glass 2, dust core No.12～14 use glass 3. Dust core No.8 is the past case being not added with glass.

Fig. 6 represents the curve chart of the initial magnetic permeability (initial stage) of each dust core being added with the glass 2 that glass transformation temperature (Tg) is 468 DEG C shown in table 3 and glass 3 that glass transformation temperature (Tg) is 442 DEG C respectively and iron loss (initial stage) and the relation of the addition of glass 2,3.It can thus be appreciated that, no matter when using which kind of glass, all there is, along with increasing of glass addition, the tendency slightly reduced in initial magnetic permeability, the initial magnetic permeability that glass addition is during 0.6wt% declines about 2～4% relative to the No.8 (past case) being not added with glass.

Additionally, according to table 3 and Fig. 6 known, iron loss (initial stage) is when using glass 2, the tendency of minimizing is presented along with the increase of addition of glass 2, on the other hand, close when using glass 3, relative to the increase of addition of glass 3, approximately fixed value is shown.

By using the glass 2,3 of lower than the heat treatment temperature in the manufacturing process of dust core 2～28 DEG C of glass transformation temperature (Tg), if adding the glass 2,3 of 0.1wt%～0.6wt%, then the initial magnetic permeability of dust core is in a ratio of equal or slightly lower with the situation without glass, and iron loss is in a ratio of equal with the situation being not added with glass interpolation and slightly improves (can reduce).

Intrinsic resistance shown in table 3 is little relative to its change of the increase of the addition of glass 2,3, and any test portion is all 10⁶More than Ω cm, it follows that have sufficiently high value as dust core. It addition, the occupation rate occupying the amorphous soft magnetic powder of dust core is 78～80%.

The curve chart of glass 2,3 addition after Fig. 7 indicates that 200 DEG C × 1000 hours of each dust core of the glass 2 that glass transformation temperature (Tg) is 468 DEG C being added with table 3 respectively and the glass 3 that glass transformation temperature (Tg) is 442 DEG C and after 250 DEG C × 1000 hours and the relation of the rate of change (%) of initial magnetic permeability. It is added with the initial magnetic permeability behind 200 DEG C × 1000 hours of dust core of glass 2 and is reduced to about-11% when the addition of glass 2 reaches 0.3wt%, but, if the addition of glass 2 is 0.6wt%, then the rate of change of initial magnetic permeability is-4%. How the addition of the rate of change no matter glass 2 being added with the initial magnetic permeability behind 250 DEG C × 1000 hours of dust core of glass 2 is shown as approximately fixed value namely about-13%.

On the other hand, the rate of change of the initial magnetic permeability being added with the dust core of glass 3 reduces along with the increase of glass addition, if adding the glass 3 of 0.6wt%, then the rate of change of initial magnetic permeability was-2% after 200 DEG C × 1000 hours, was-8% after 250 DEG C × 1000 hours.

The curve chart of the addition of the glass 2,3 after Fig. 8 indicates that 200 DEG C × 1000 hours of each dust core of the glass 2 that glass transformation temperature (Tg) is 468 DEG C being added with table 3 respectively and the glass 3 that glass transformation temperature (Tg) is 442 DEG C and after 250 DEG C × 1000 hours and the relation of iron loss rate of change (%).

As shown in table 3 and Fig. 8, iron loss rate of change after being added with 200 DEG C × 1000 hours of dust core of glass 2 and after 250 DEG C × 1000 hours increases equally along with the increase of the addition of glass 2, if adding the glass 2 of 0.6wt%, then iron loss rate of change respectively+80% ,+138%. On the other hand, it is little relative to its change of the increase of the addition of glass 3 to be added with the iron loss rate of change behind 200 DEG C × 1000 hours of dust core of glass 3 and after 250 DEG C × 1000 hours, and respectively+44% ,+58%.

Known accordingly, by making the addition of glass 2,3 be 0.1～0.6wt%, initial magnetic permeability (initial stage) can be set to the degree equal with the situation (No.8) being not added with glass, further, it is possible to improve the heat stability (heat-resistant quality) of initial magnetic permeability.It addition, iron loss (initial stage) becomes roughly equal with past case (No.8) or is reduced to below.

Glass 1 and glass 2,3 are contrasted, the glass transformation temperature (Tg) of glass 1 is 280 DEG C, lower about 200 DEG C than the heat treatment temperature (470 DEG C) implemented in the manufacturing process of dust core, but, the glass transformation temperature (Tg) of glass 2,3 is only low 2～28 DEG C than the heat treatment temperature (470 DEG C) implemented in the manufacturing process of dust core.

Additionally it can be seen that when glass 1 is for dust core, although the rate of change of the initial magnetic permeability after 180 DEG C × 1000 hours is suppressed low, but there is the tendency that beginning permeability easily declines to a great extent. On the other hand, when glass 2,3 is for dust core, initial magnetic permeability (initial stage) can become the degree equal with the situation being not added with glass, and after not only 180 DEG C × 1000 hours, and the rate of change of initial magnetic permeability is also suppressed low after 250 DEG C × 1000 hours.

In addition we know, as the glass for dust core, glass 2,3 has the heat stability of higher initial magnetic permeability compared with glass 1, is therefore more highly preferred on the one hand at this.

The experiment of glass and magnetic particle (compound be added with)

The Fe made using water atomization to make_77at%Cr_1at%P_9.23at%C_2.2at%B_7.7at%Si_2.87at%It is that amorphous soft magnetic alloy powder, silicone resin, stearic acid Asia lead and NiZn ferrite powder (magnetic particle) mix and make mixture. This NiZn ferrite powder uses Kawasaki Steel KN1-106GMS, is dried and begins to use after pulverizing utilizing ball mill to carry out 30 hours.

And then, the Fe that water atomization will be used to make_77at%Cr_1at%P_9.23at%C_2.2at%B_7.7at%Si_2.87at%Be that amorphous soft magnetic alloy powder, silicone resin, stearic acid Asia be plumbous, NiZn ferrite powder and glass 2 or glass 3 mix respectively and make mixture. Additionally, the use level of the silicone resin in this mixture is 2.0wt% relative to the quality of soft magnetic powder, the use level of stearic acid Asia lead is 0.3wt% relative to the quality of soft magnetic powder, the use level of NiZn ferrite powder relative to the quality of soft magnetic powder be 0.3,0.6,1.2wt%, the use level of glass 2,3 relative to soft magnetic powder quality respectively 0,0.1,0.3,0.6wt%.

It follows that be filled in mould by this mixture, carry out press molding with contact pressure 1470MPa, thus making the ring-type test portion of external diameter 20mm × internal diameter 12mm × thickness 6.8mm. The ring-type test portion obtained is carried out the heat treatment of 1 hour with 470 DEG C in nitrogen gas atmosphere, thus making dust core.

Quality according to the ring-type dust core obtained calculates the density of magnetic core with profile cun method, and the numerical computations of collaboration amount goes out the occupation rate (with reference to numerical expression 2) of amorphous soft magnetic alloy powder. Additionally, SuperMegohmmeter (DKK-TOA SM-8213) is used to measure the intrinsic resistance of ring-type dust core, it is wound around copper cash to ring-type dust core, use ImpedanceAnalyzer (HP4192A) to measure initial magnetic permeability, use BHAnalyzer (the rugged communication system of rock) to measure iron loss when frequency 100kHz, Bm=100mT. Heat resistant test measures as follows, is put into by ring-type dust core in the drying oven of 200 DEG C, 250 DEG C in an atmosphere, measures the initial magnetic permeability after keeping 1000 hours and iron loss.Each measurement result illustrates in table 4.

[table 4]

Fig. 9 indicates that the curve chart of the ferritic addition of NiZn in dust core No.15～18 (be added with NiZn ferrite, be not added with glass) and initial magnetic permeability (initial stage) and the relation of iron loss (initial stage). Dust core No.15 is free from glass and the past case of NiZn these both sides of ferrite.

In addition we know, along with the increase of the ferritic addition of NiZn, initial magnetic permeability (initial stage) and the iron loss (initial stage) of dust core all increase to some extent.

Figure 10 indicates that the rate of change of the ferritic addition of NiZn when dust core No.15～18 (be added with NiZn ferrite, be not added with glass) are exposed in the heat resistant test of 200 DEG C and 250 DEG C × 1000 hours and initial magnetic permeability and the curve chart of the relation of iron loss rate of change. Increase along with the ferritic addition of NiZn, the rate of change of initial magnetic permeability is negative value, its absolute value becomes larger, if the ferritic addition of NiZn is 1.2wt%, then after 200 DEG C × 1000 hours, after 250 DEG C × 1000 hours respectively-12% ,-18%. Iron loss rate of change monotone decreasing in the heat resistant test of 200 DEG C, in the heat resistant test of 250 DEG C, the ferritic addition of NiZn is 0.3Wt% and starts to reduce after illustrating maximum, if the ferritic addition of NiZn is 1.2wt%, it is shown as+6% ,+34%.

Figure 11 indicates that the addition of glass 2,3 of dust core No.19～24 (being added with NiZn ferrite, glass 2,3) and the curve chart of the initial magnetic permeability (initial stage) of dust core and the relation of iron loss (initial stage). It is added with glass 2 in dust core No.19～21, dust core No.21～24 are added with glass 3. It should be noted that as shown in table 4, in dust core No.19～24, the ferritic addition of NiZn is unified for 0.6wt%.

It addition, the addition of the glass 2,3 of Figure 11 is the value that the initial magnetic permeability (initial stage) during 0wt% and iron loss (initial stage) have the dust core No.17 that NiZn ferrite is 0.6wt%.

According to Figure 11 and table 4 known, initial magnetic permeability presents the tendency slightly reduced along with the increase of the addition of glass 2,3, but, if the addition of glass 2,3 is 0.1wt%, then compared with the dust core No.15 (past case) being not added with glass and NiZn these both sides of ferrite, it is possible to increase initial magnetic permeability.

On the other hand, the addition of the not interdependent glass 2,3 of iron loss (initial stage) and be shown approximately as fixed value, but by adding glass 2, relative to dust core No.17 (glass addition is 0wt%), iron loss (initial stage) has the tendency slightly reduced, by adding glass 3, relative to dust core No.17 (glass addition is 0wt%), there is the tendency that iron loss (initial stage) increases.

The curve chart of glass addition when Figure 12 indicates that the heat resistant test that dust core No.19～24 (being added with NiZn ferrite and glass 2,3) carries out 200 DEG C × 1000 hours and 250 DEG C × 1000 hours and the relation of the rate of change of initial magnetic permeability.

It should be noted that the rate of change that the addition of the glass 2,3 of Figure 12 is initial magnetic permeability during 0wt% becomes the value of the dust core No.17 that NiZn ferrite is 0.6wt%.

The rate of change of the initial magnetic permeability according to Figure 12 and table 4 it can be seen that after 200 DEG C × 1000 hours is negative value, but its absolute value of increase being as the addition of glass 2 is gradually reduced. But, when being added with glass 3, if addition is 0.3～0.6wt%, then the rate of change of initial magnetic permeability does not substantially change for-3%.

Next, the rate of change of the initial magnetic permeability according to Figure 12 and table 4 it can be seen that after 250 DEG C × 1000 hours is negative value, but when being added with glass 2, along with the increase of glass addition, the rate of change (absolute value) of initial magnetic permeability is gradually reduced. On the other hand, although the rate of change of initial magnetic permeability when being added with glass 3 is also for negative value, but the rate of change of initial magnetic permeability (absolute value) reduces to some extent compared with the situation (dust core No.17) being not added with glass. But, for the rate of change of initial magnetic permeability during for being added with glass 3, even if the change of glass addition, the also substantially not change of the rate of change of initial magnetic permeability now.

The curve chart of glass addition when Figure 13 indicates that the heat resistant test that dust core No.19～24 (being added with NiZn ferrite, glass 2,3) is applied with 200 DEG C and 250 DEG C × 1000 hours and the relation of iron loss rate of change.

It should be noted that the addition of the glass 2,3 of Figure 13 is iron loss rate of change during 0wt%, there is the value of the dust core No.17 that NiZn ferrite is 0.6wt%.

It is roughly the same tendency that iron loss rate of change represents when heat resistant test temperature is 200 DEG C and 250 DEG C. When being added with glass 2, even if addition increases to 0.3wt% and also illustrates that roughly the same iron loss rate of change, if addition increases to 0.6wt%, then iron loss rate of change becomes big.

On the other hand it can be seen that when being added with glass 3, when addition is 0.1wt%, iron loss rate of change becomes minimum, if increasing addition further, then iron loss rate of change becomes big.

According to table 4 and Figure 11 to Figure 13 known, added glass and NiZn ferrite by compound, it can be ensured that relatively higher initial magnetic permeability (initial stage), and also the heat stability of initial magnetic permeability can be improved, but also iron loss rate of change can be reduced, improve the heat stability of iron loss. Particularly with the dust core (especially dust core No.22) being added with the glass 3 that glass transformation temperature (Tg) is 442 DEG C, it is possible to make iron loss rate of change effectively reduce, thus improving the heat stability of iron loss further.

As mentioned above, in the present embodiment, the addition of glass is being set as, and relative to the quality of soft magnetic powder be more than 0.1 mass %, below 0.6 mass %, and when adding magnetic particle further, the addition of magnetic particle is set to, and the quality relative to soft magnetic powder is for more than 0 mass % and be below 0.6 mass %.

(by adding the characteristic test of each dust core of the different each glass of composition)

Make the multiple glass possessing following glass composition.

[table 5]

In each glass 4～18 of table 5, meter feedstock and become the use level of the regulation shown in table 5, put it into platinum crucible and be pre-mixed, then use electric furnace to be dissolved in air atmosphere. The design temperature of electric furnace is 1000～1300 DEG C.

It follows that take out platinum crucible from electric furnace, glass is dissolved body and casts in cast iron casting mould and obtain glass. After utilizing mortar by this glass coarse pulverization, ball mill is used to carry out pulverizing and obtaining glass powder.

Additionally, the glass blocks of 3mm × 3mm × 20mm is cut out from the part casting the glass obtained, carry out eliminating the annealing of deformation, then use hot device analysis device (motor TMA8310 of science) to measure glass transformation temperature, glass transition temperature (yield temperature) and thermal coefficient of expansion.The use level of each glass 4～18 made and glass transformation temperature, glass transition temperature (yield temperature) and thermal coefficient of expansion illustrate in table 5.

It addition, be also attached with proportion and vitrification point in table 5.

Then, mixture is made in the mixing such as each glass shown in table 5, amorphous soft magnetic alloy powder, silicone resin and stearic acid Asia lead. The amorphous soft magnetic alloy powder used is the Fe made by water atomization_77at%Cr_1at%P_9.23at%C_2.2at%B_7.7at%Si_2.87at%It it is amorphous soft magnetic alloy powder.

Additionally, the use level of the silicone resin in this mixture is 2.0wt% relative to the quality of soft magnetic powder, the use level of stearic acid Asia lead is 0.3wt% relative to the quality of soft magnetic powder, and the use level of each glass is 0.6wt% relative to the quality of soft magnetic powder.

It follows that be filled in mould by this mixture, under contact pressure 1470MPa, carry out press molding, thus making the ring-type test portion of external diameter 20mm × internal diameter 12mm × thickness 6.8mm. By the ring-type test portion obtained in nitrogen gas atmosphere, at 470 DEG C, carry out 1 hour heat treatment and make dust core.

In an experiment, the coiling of copper cash is carried out to ring-type dust core, use ImpedanceAnalyzer (HP4192A) to measure initial magnetic permeability, use BHAnalyzer (the rugged communication system of rock) to measure iron loss when frequency 100kHz, Bm=100mT. In heat resistant test, ring-type dust core is put in an atmosphere in the drying oven of 200 DEG C or 250 DEG C, measure the initial magnetic permeability after keeping 1000 hours and iron loss. It addition, to dust core compressive press forces and using compression stress when being damaged to as maximum intensity unshakable in one's determination. Each measurement result is shown in table 6.

[table 6]

The hurdle of the glass shown in table 6 is corresponding with the glass No of table 5. It should be noted that in table 6, the value of " μ ' (100kHz) ", " iron loss (100kHz, 100mT) " in the hurdle of 200 DEG C, 250 DEG C is initial value. Although the value of the respective initial value of identical dust core No is slightly different, but this is because use other dust cores of making at identical conditions to measure, the rate of change using each dust core each value after 200 DEG C, 250 DEG C keep 1000 hours at each temperature respectively is measured.

Figure 14 indicates that the curve chart of the initial magnetic permeability (initial stage) of each dust core shown in the hurdle of 200 DEG C of table 6. In fig. 14, the glass transformation temperature Tg of the glass added to each dust core is transverse axis, and the thermalexpansioncoefficientα of glass is the longitudinal axis. Therefore, Figure 14 does not include the experimental result being not added with the dust core of the past case of glass.

It addition, the curve chart of the iron loss (initial stage) of each dust core shown in hurdle of Figure 15 is table 6 200 DEG C. In fig .15, the glass transformation temperature Tg of the glass added to each dust core is transverse axis, and the thermalexpansioncoefficientα of glass is the longitudinal axis. Therefore, the experimental result being not added with the dust core of the past case of glass is not included in fig .15.

It addition, Figure 16 is the rate of change (200 DEG C, 1000 hours) of the initial magnetic permeability of each dust core shown in table 6, Figure 17 indicates that the curve chart of the relation of the iron loss rate of change (200 DEG C, 1000 hours) with each dust core. At Figure 16, Tu17Zhong, the glass transformation temperature Tg of the glass added to each dust core is transverse axis, and the thermalexpansioncoefficientα of glass is the longitudinal axis. Therefore, Figure 16, Figure 17 do not include the experimental result being not added with the dust core of the past case of glass.

Firstly, since the heat treatment temperature during by each dust core compression molding of table 6 is 470 DEG C, so the dust core being added with the glass with the glass transformation temperature (Tg) higher than 470 DEG C is entirely comparative example.

In Figure 14 to Figure 17, the line (part) of the glass transformation temperatures of 470 DEG C (Tg) is pulled out line. The right side of this line is comparative example.

By observing the experimental result of table 6, Figure 14 and Figure 16, lower than 470 DEG C by the glass transformation temperature (Tg) that makes glass, it is obtained in that the initial magnetic permeability (initial stage) that comparison is high, further, the rate of change (absolute value) of initial magnetic permeability can be effectively reduced compared with past case (glass is without adding). Then it can be seen that the heat stability of initial magnetic permeability can be effectively improved according to the present embodiment. It addition, the glass transformation temperature of glass (Tg) is preferably more than 360 DEG C.

It addition, the thermalexpansioncoefficientα (× 10 of glass^-7/ DEG C) it is preferably 60～110, or be about 60～90. It can thus be appreciated that, it is possible to more effectively reduce the absolute value of the rate of change of initial magnetic permeability, it is possible to realize the raising of heat stability.

In the present embodiment it can be seen that the rate of change (absolute value) of initial magnetic permeability after 200 DEG C, 1000 hours can be suppressed within 4%, it is preferred within 3%, more preferably within 2%, more preferably within 1.5%.

In addition we know, for iron loss, by making the glass transformation temperature (Tg) of glass become the value that 360 DEG C less than 470 DEG C, it is possible to increase heat stability.

Claims (8)

1. a dust core, it is by will have the mixture compression molding of soft magnetic powder and insulating properties jointing material and carry out heat treatment and obtain, it is characterised in that

Described insulating properties jointing material has binding resin and glass,

The glass transformation temperature (Tg) of described glass is lower than described heat treated temperature, and the glass transformation temperature (Tg) of described glass is more than 280 DEG C and in the scope of less than 470 DEG C,

The thermal coefficient of expansion of described glass is 60～110 × 10^-7/ DEG C,

Described insulating properties jointing material surrounds the surface of described soft magnetic powder, and is present between described soft magnetic powder,

The content of described glass relative in the scope that the quality of described soft magnetic powder is more than 0.1 mass %, below 0.60 mass %,

Described glass at least has P₂O₅、B₂O₃And BaO, P₂O₅Ratio of components a be 40～60mol%, B₂O₃The ratio of components d that ratio of components c is 5～45mol%, SnO that ratio of components b is 2～20mol%, BaO be 0～45mol%, Al₂O₃Ratio of components e be 0～15mol%, and meet the relation of a+b+c+d+e≤100mol%.

2. dust core according to claim 1, it is characterised in that

The difference of described heat treated temperature and described glass transformation temperature is 2～100 DEG C.

3. dust core according to claim 1, it is characterised in that

Described glass is part diffusion, fusion in resin.

4. dust core according to claim 1, it is characterised in that

Al₂O₃Ratio of components e be 2～15mol%.

5. the dust core according to any one of Claims 1 to 4, it is characterised in that

Li₂The ratio of components f of O is 0～1mol%, CeO₂Ratio of components g be 0～10mol%, TiO₂Ratio of components i be 0～1mol%, and meet the relation of a+b+c+d+e+f+g+h+i=100mol%.

6. the dust core according to any one of Claims 1 to 4, it is characterised in that

The glass transformation temperature (Tg) of described glass at 360 DEG C less than in the scope of 470 DEG C.

7. the dust core according to any one of claim 1-4, it is characterised in that

The thermal coefficient of expansion of described glass is 60～90 × 10^-7/℃。

8. the manufacture method of a dust core, it is characterised in that including:

Using soft magnetic powder, the operation generating mixture as binding resin and the glass powder mixing of insulating properties jointing material;

By described mixture compression molding, then carry out heat treated operation with the heat treatment temperature higher than the glass transformation temperature of described glass powder (Tg),

The content of described glass powder relative in the scope that the quality of described soft magnetic powder is more than 0.1 mass %, below 0.60 mass %,

Described glass powder at least has P₂O₅、B₂O₃And BaO, P₂O₅Ratio of components a be 40～60mol%, B₂O₃The ratio of components d that ratio of components c is 5～45mol%, SnO that ratio of components b is 2～20mol%, BaO be 0～45mol%, Al₂O₃Ratio of components e be 0～15mol%, and meet the relation of a+b+c+d+e≤100mol%,

The glass transformation temperature (Tg) of described glass is more than 280 DEG C and in the scope of less than 470 DEG C,

The thermal coefficient of expansion of described glass is 60～110 × 10^-7/ DEG C,

Described insulating properties jointing material surrounds the surface of described soft magnetic powder, and is present between described soft magnetic powder.